1. Field of the Invention
The present invention relates to a method for measuring fractions of hydrocarbon fluids using optical spectroscopy.
2. Description of Related Art
It is often desirable for many reasons to characterize the compositions of hydrocarbon fluids, such as crude oil. For example, the behavior of a hydrocarbon fluid depends, at least in part, on the composition of the hydrocarbon fluid. Proper reservoir management utilizes data concerning pressure and temperature of the reservoir along with the composition of the hydrocarbon reservoir fluids. Moreover, the mixing of different hydrocarbon fluids during transportation and/or storage of hydrocarbon fluids can cause perturbation of the fluids system. For example, the presence of incompatible fluids can result in precipitation of solids and the deposition of such solids within transportation and/or storage equipment.
One of the more common methods used to characterize the compositions of hydrocarbon fluids involves the separation of such fluids into four fractions, i.e., saturates, aromatics, resins, and asphaltenes, then weighing each fraction to determine the composition of the hydrocarbon fluid. Such weight-based measurements are cumbersome and costly, as substantial quantities of solvents, adsorbent, and oil are required for testing accuracy.
There are methods for characterizing the compositions of hydrocarbon fluids that are well known in the art, however, considerable shortcomings remain.